MPC5577C - Mission Profile Pt1 calculation

[davidfantl]

There is one question for NXP related to the actual value of p_t1 (row 7, column E of the spreadsheet). Based on MPC5777C datasheet data for power dissipation 1.6W (table 24 of MPC5777C datasheet) and junction temperature (Table 55 of MPC5777C datasheet) for a unit the value of the value of p_t1 should be ~ 2. Can you explain how you got a value of 1.53 for p_t1 using IEC TR 62380 7.3.1 (which is the standard called out in the comment on cell A1)?

[davidfantl]

adding SS for Clarification

[aarul · Accepted solution]

Hi David

The p_t1 is temperature stress factor that is calculated based on TR62380. It is calculated using this equation

exp (3480* [(1/328) - 1/(273+t1+power_dissipation*Rj*0.001))

So the value for power_dissipation=1000mW, T1=40C and Rj = 28.8 is 1.53

Hope this helps you to check the calculations. Let me know if you still see issues. 

Regards

-Aarul